1. Field of the Invention
This invention relates to solar cell electronic devices.
2. Description of the Related Art
An example of a solar cell electronic device is a digital wrist watch equipped with a solar panel. In this type of digital wrist watch, a liquid crystal display section is mounted on the front side of an exterior case, and a cover glass is mounted over the liquid crystal display section. The solar panel is mounted on the back face of the cover glass.
The solar panel is disposed at a predetermined distance from the cover glass to suppress transmission of the external impact on the wrist watch via the cover glass. Further, the solar panel is often disposed over a large area in the planar central portion of the cover glass to provide a large surface area for receiving light.
Further, in many cases, the cover glass is configured so as to be removable from the exterior case by itself. In this case, a packing is interposed between the exterior case and the cover glass to provide sealing.
In this way, for example, only the cover glass needs to be replaced when it is damaged, and the economical burden on a user can be reduced. Further, the packing interposed between the exterior case and the cover glass can prevent entry of dust and other foreign objects into the exterior case. For example, dust and other foreign objects entered between the exterior case and the solar panel during the assembly of a digital wrist watch can be removed by removing the cover glass, and the watch may then be reassembled to improve the product yield (see, for example, JP-A-11-337670).
In the foregoing related art, the cover glass is removed from the exterior case by pressing the cover glass outwardly from the inner side of the exterior case. Here, because the solar panel is disposed over a larger area on the back face of the cover glass, it is difficult to directly press the cover glass, and instead the solar panel is directly pressed to push out the cover glass with the solar panel. Further, because of the packing interposed between the exterior case and the cover glass, a greater pressure is needed to remove the cover glass.
This is problematic because it may damage the solar panel in the process of removing the cover glass.
Further, because the solar panel is disposed on the back face of the cover glass, the solar panel blocks the space surrounded by the cover glass and the solar panel, and the space surrounded by the solar panel and the caseback attached to the back side of the exterior case.
For a waterproof test of a wrist watch, a method is available in which the finished exterior case with a caseback is heated to increase the temperature inside the exterior case and vaporize the trace amount of the entered moisture, and thereafter the cover glass surface is cooled to check for any condensation on the inner surface of the cover glass and to determine whether water has entered the exterior case. However, a waterproof test performed by using this method is problematic, because the solar panel blocking the space inside the exterior case restricts the movement of the air inside the exterior case, and makes it difficult to accurately perform the waterproof test.